INCORPORATION BY REFERENCE: Applicant(s) hereby incorporate herein by reference, any and all U.S. patents, U.S. patent applications, and other documents and printed matter cited or referred to in this application.
1. Field of the Invention
This invention relates generally to electric lamps and decorative shades therefor, and more particularly to a double lamp shade with a dichroic coating presenting unusual visual effects when illuminated.
2. Background and Description of Related Art
With respect to lamp shades used for covering a light source, except for opaque shades, such shades generally change their appearance when the light source is illuminated. Most generally, translucent shades become illuminated from the light source and present a desired appearance. Transparent shades transmit light from the source directly but also may present a novel appearance with certain parts of the shade being illuminated in desired ways.
It is known to use colored lights in combination to produce various color displays on a translucent shade. Two-piece lamp shades having an inner shade and an outer shade are known to be used to produce interesting effects as in the Ireland-Stacy reference described below.
It is known to use optical thin films of transparent and semi-transparent materials having thicknesses approximating one-fourth the wavelength of the light that it is desired to transmit through the films, in multiple layers, in order to fabricate optical filters. Such filters may be designed to pass selected wavelength bands of light energy while rejecting others. When the optical filters are held to a desired thickness uniformly across a workpiece, a uniform effect is produced, that is, the visual effect is that certain colors of light appear to the observer. When the thicknesses of the optical films are allowed to vary across the workpiece, the visual effect is that the colors produced vary from point to point over the workpiece. Such a film may be deposited that will produce a rainbow effect. This phenomenon is used in the present invention.
The following art defines the present state of this field:
Neal, Jr., U.S. Pat. No. 4,254,455 describes a reflector for use in a dental, medical or other lighting device wherein light from a light source is reflected thereby in a predetermined pattern for illumination of a desired zone. The reflector is formed of a glass substrate of predetermined shape and has a dichroic coating on the front surface for reflecting a substantial portion of visible light and for allowing infrared and other undesirable energy along with some unreflected visible light to pass therethrough so that cool light only is reflected and a diffuser coating on the rear surface for diffusing light passing through the glass substrate to reduce undesirable glare from the rear of the reflector. The diffuser coating is preferably a ceramic frit.
Ireland-Stacy, U.S. Pat. No. 5,975,725 describes a shade for covering a light source and a process for making the shade. The shade comprises an inner member and an outer member where the outer member is connected to the inner member. At least one inclusion is located between the inner member and the outer member wherein covering the light source with the shade enables viewing of the inclusion therein when the light source is in an on state and substantially prohibits viewing of the inclusion therein when the light source is in an off state.
Scott, et al; U.S. Pat. No. 4,793,908 describes a method of fabricating multiple layer, solid, thin films on a substrate having a surface to be coated, the method providing control over the thickness, stoichiometry, and morphology of each separate layer formed by a method comprising the steps of: A. forming a first ion beam from an inert gas; B, bombarding a target surface with said first ion beam in a vacuum chamber to generate a vapor cloud composed of the target material atoms by the process of sputtering; C. adjusting the respective positions of the substrate surface for coating and the target surface to promote the condensation of the vapor upon the substrate surface for coating; D. forming a second ion beam, the second ion beam""s ions being formed from a mixture of inert and reactive gases; E. bombarding the substrate surface simultaneously with the second ion beam to promote a chemical reaction between the target vapor atoms and the chemically reactive gas ions as the target atoms and the chemically reactive gas ions impinge upon the substrate surface for coating, the resulting chemical compound building up in thickness as a homogeneous thin solid film layer; F. positioning an alternative target material in the place occupied by the previous one; G. repeating the above method steps to produce each successive thin solid film layer of different material formed upon each previous layer.
The prior art teaches the concept of using an inner and an outer lamp members to present the effect of viewing an inclusion only when the lamp is illuminated, but not otherwise. The prior art also teaches the use of thin film coatings in a lamp to enable only certain visible portions of light to pass while reflecting others. However, the prior art does not teach the use of a multi-layer thin optical film coating of a lamp shade for producing a rainbow visual effect when a lamp is illuminated, but not otherwise. The present invention fulfills these needs and provides further related advantages as described in the following summary.
The present invention teaches certain benefits in construction and use which give rise to the objectives described below.
The present invention comprises a lamp assembly having a shade system covering a light source. The shade system includes an outer shade envelope made of a transparent material such as glass or plastic. This outer shade envelope is treated with a multilayer optical coating on its in-facing surface. An inner shade envelope is positioned within the outer shade, and this shade is made of translucent material, again generally frosted glass or plastic. The shades are mounted concentrically. A light source such as an electric lamp is positioned at the center of the inner shade envelope. The invention presents three different appearances to a viewer. Viewing the lamp assembly from one side, when the lamp is not illuminated, the inner shade is not visible, and only the outer shade envelope may be seen, and it appears to be a gray metallic color. From this same viewpoint, when the lamp is illuminated, the outer shade appears to be transparent while the inner shade, appears to have a multicolored pattern such as a rainbow. In an alternate embodiment, the inner shade may be constructed of two individual envelopes joined integrally. The light directed downwardly, as for illuminating a restaurant table, does not have the various colors seen from the side of the outer shade but rather is the color of light produced by the electric lamp.
A primary objective of the present invention, is to provide an apparatus and method of use of such apparatus that provides advantages not taught by the prior art.
Another objective is to provide such an invention capable of producing an interesting visual effect on the shade when seen from one side, while producing a conventional illumination below.
A further objective is to provide such an invention capable of having the interesting visual effect only when the interior lamp is illuminated but not otherwise.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.